Abstract
Inhomogeneous deformation of rolled metals with considerably large reductions has been studied by many investigators. But it appears that the study on rolled metals with small reduction such as temper rolling is very few.
This experiment was carried out to make clear the aspect of inhomogeneous deformation which might be necessary on discussing the test results on strain aging which plays a very important role in temper rolled steel sheet.
The sheet metal used in this experiment is 0.06%C steel, with 1.2mm thickness.
At first, the elongation of the sheet in rolling direction caused by temper rolling was measured. The temper rolled sheet was seemingly elongated and reduced uniformly, but distribution of Micro-Vickers hardness, residual stress and etching rate from the rolled surface to the center of thickness revealed that the material was subjected to inhomogeneous deformation.
And the condition of friction in the interface between work-roll and sheet was found to have a large effect on the deformation.
The test results are summerized as follows.
(1) The temper-rolled sheet steel is deformed inhomogeneously in its thickness direction and the inhomogeneity depends on the rolling reduction. The inhomogeneity seems to have different aspects with a border line at a reduction of some 0.25%.
(2) The change of spread of a specimen by temper-rolling is almost equal to the value calculated by E. Siebel's formula.
(3) Temper rolling is influenced considerably by frictional condition of the surfaces. If there is a slight difference of frictional conditions on the sheet surfaces, roll-working becomes limp; the surface with a larger frictional force is rolled more severely.
